Coaxial cables or coaxial cable assemblies are often prone to damage from repeated fastening and unfastening of the cable connectors to mating connectors. This is particularly true of a type of cable assembly commonly known as a “test” cable assembly. A test cable assembly comprises a coaxial cable of any kind and a connector of any kind attached to the cable on one or both ends thereof. Test cable assemblies perform a vital, specific and unique function in the electronics industry. Test cable assemblies are used to accurately measure product performance during and after the manufacturing process.
To assure the accuracy of test measurement data, test cables are themselves built and measured very accurately. Their electrical and mechanical performance characteristics are determined and then defined for a specific purpose or use. Users desire test cables to withstand or endure constant and continual connecting and disconnecting to products and/or other interconnect devices without breaking, failing or degrading mechanically or electrically in any way. Users desire test cables to maintain their original performance characteristics even when used in harsh conditions and environments, and even if misused or mishandled. Thus, designing and manufacturing rugged, long life test cables has grown to be an industry unto itself.
Coaxial cables—especially test coaxial cables—typically suffer from two common failure modes: the connector separates or loosens from the cable and/or the coaxial outer conductor is degraded in one of several ways during repeated use when fastening and unfastening the coaxial cable connector to a mating connector. This is caused by a twisting or torquing motion induced into the attachment area between the connector and the coaxial cable by the normal mating together of male and female connectors. Referring to FIG. 1, for example, a coaxial cable assembly 11 having a connector 13, an outer conductor or braid 15, and an outer jacket 17 exhibits typical damage to the outer conductor in a failure-prone area adjacent to the connector as a result of such repeated twisting or torquing action.
To function properly coaxial connectors must be physically and securely connected to the cable outer conductor. When this connection is compromised either partially or fully the cable assembly is generally classified as failed. This invention is applicable to all coaxial cables regardless of cable construction and all coaxial connectors regardless of series (i.e., SMA, Type N, etc), configuration (i.e., straight, right angle, etc) or gender (i.e., male or female).
Coaxial cables can be of virtually any length and design. Such cables generally comprise an inner or center conductor of any construction or metal surrounded by an insulating material of any kind and an outer conductor of any design. The outer conductor is generally made of individual metal wires or solid metal, and is surrounded by an outer insulating cover of any material. The cable includes a male or female coaxial connector of virtually any design or construction, but has as one of its components a solid outer housing of any material attached to one or both ends of a coaxial cable center conductor and outer conductor by any internal connector construction or design.
A failure mode can be more specifically described as one in which the outer conductor cracks, breaks, rips or separates either partially or fully immediately behind or in the general area behind the coaxial connector from rotational torque stress induced during the mating/unmating sequence with connectors of the opposite gender and/or pulling and contracting stress induced during flexing and bending of the coaxial cable during general handling, thus degrading both the mechanical and electrical product specifications.
Typical solutions include applying a strain relief to the coaxial/connector attachment area. The two most common solutions are the application of 1) heat shrink strain relief tubing, and 2) molded plastic “boots”. These methods are effective at prohibiting cable or cable/connector interface damage from bending or flexing the cable at the attachment area. However, both of these methods are ineffective at prohibiting damage from radial forces such as the torque or twisting forces that are induced along a longitudinal axis of the cable and connector during the mating together of connectors.
Connectors with cable clamping mechanisms or separate clamping mechanisms have been used to address this problem. While this may be effective for some cables most notably “corrugated” cable or cables with solid metal outer conductors, it is not appropriate, effective or recommended for the vast majority of flexible and all “tin soaked” coaxial cables. Clamps will squeeze and thereby physically deform the cable. The industry considers deformed (that is, no longer perfectly circular) coaxial cables to be failed or at best degraded when used at radio or microwave frequencies.
Based on the foregoing, it is an object of the present invention to provide a coaxial cable assembly and a handgrip device used therewith that overcomes the above-mentioned drawbacks and disadvantages associated with prior coaxial cable assemblies.